Grinding apparatus



Jan. 7, 1947.

L. NIEMAN GRINDING APPARATUS Filed Feb. 7, 1945 5 Sheets-Sheet l @2p/22% auf Jan@ 7, 1947.

GRINDING APPARATUS Filed Feb. 7, 15545 s sheets-sheet 2 L. L. NIEMAN 2,414,0 56

l Jan. 7, 1947.

L. L. NIEMAN 2,414,056

@BINDING APPARATUS Filed Feb. 7, 1945 5 sheets-sheet s jzy.

5a zo Y 57 47` I' I 4Z 7 gf@ eguf Patented Jan. 7, 1947 UNITED STATES PATENT orns v A' Lee L. Nieman, ohieago, nl.

' Application February v, 1945, seria1No.5i6,591

l -This invention relates to improvements in grinding apparatus.l and is more particularly concerned with apparatus of this type adapted for use in finishing plaster cast plate dentures.

An object of the present invention resides in the provision of a pair of finishing wheels mounted, one behind the other, upon a rotatable shaft journaled within a suitable housing and in which saidV wheels are accessible for finishing plaster cast plate dentures from adjacent one face of the housing.

Another object of this invention is to provide an apparatus of this type embodying improved means for mounting and guiding plaster casts into position with one of the finishing wheels to provide-casts of uniform predetermined contour.

A further object of this invention is to provide an apparatus f this type embodying improved means for collecting and confining particles of plaster removed from the plaster casts during the mshing operation.` f

This invention embodies `other novel features, details of construction and arrangement of parts which are hereinafter-set forth in the specification and claims and illustrated in the accompanying drawings wherein:

Fig. 1 is a front elevational View showing a grinding Vapparatus `embodying features of this invention., h Y Y Fig. 2 is a fragmentary sectional view taken along the line 2-2 of Fig. 1 showing an air funnel which `is adapted to be detachably connected to the front face of the housing to enclose one of the air inlet openings formed therein.

Fig. 3 is a sectional view taken along the line 3--3 of Fig. 1.

Fig. 4 is a fragmentary sectional View taken along the line 4-4 of Fig. 1 showing an improved turntable means for mounting and guiding a plaster cast into engagement with a grinding wheel.

Fig. 5 is a fragmentary sectional view taken along the line 5 5 of Fig. 4.

Referring now to the drawings for a Ibetter understanding of this invention, the grinding apparatus is shown as comprising a housing 6 formed with front wall 'I, back wall 8, side walls 9 and II, a bottom I2 and a top I3. An electric motor I4 is supported within the housing upon suitable brackets I6 and has its shaft detachably connected by means of'a collar I1 to a shaft I8.

A relatively small diameter grinding or cutting wheel I9 is detachably mounted on the outer end of the shaft I8 by any suitable means (not 2 Claims. (Cl. 51-127) shown), and is adapted to project outwardly through an air inlet opening 2| provided in the front plate 'I of thehousing. A relatively large diameter disc-shaped grinding wheel 22 is secured on the shaft I8 adjacent the inner sidefof the front wall 1. A suction air inlet opening 23 is formed in the vfront wall 'I of the housing ad-` jacent the opening 2|, and `is shaped to permit insertion therethrough ofv a `plaster cast 2U of a plate denturefor grinding engagement with the side of the wheel 22. h

A centrifugal blower 24 is also secured on the shaft I8 between the motor and the grinding wheel 22 for causing direct air to flow inwardly through the openings 2I and 23 and thence upwardly through an outlet passage 26 to the interior of a bag 21 or other dirt storage receptacle. A partition 28 is provided within the housing 6 between the motor I4 and the blower 24, and a partition 29 is provided between the grinding Whee1 22 and the blower 24. The partitions 28 and 29 serve to form a blower compartment 3| within the housing. The partition 29 is preferably formed with an arcuate inwardly sloping face 32 for directing air and particles of plaster toward a centralxopening 33 leading to the blower compartment.

The bag 21 is formed of cloth or other suitable material to permit the `escape of air therefrom and to retain any dirt or particles of plaster delivered thereto by the blower 24.` The mouth of the bag` is detachably connected to an annular boss defining the upper end of the outlet passage 26 by means of a clamping ring 34. 'A vacuum bag compartment 36 is provided in the housing, and a grilled opening 31 is formed on the back wall 8 to permit the passage of air from lthe bag compartment 36 to the exterior of the housing. A cover 38 is hingedly connected to the back Wall 8 of the housing at 39 and is provided with a suitable lifting knob 4I on its forward edge for raising the cover to permit access to the bag 21.

A shelf 42 is supported on the front Wall 1 of the housing by means of brackets 43 to receive three roller mounting bolts 44, 44a and l4422 having sleeve rollers 46 journaled thereon. A turntable 4l is mounted on the shelf 42 and provided with a plurality of cam surfaces 48, 48a, 49 and 49a, for operative engagement with sleeve rollers 46 to dene the line of travel of the turntable. Abutment shoulders 5I and 6Ia are provided at the inner ends of the cam surfaces 48, 49 and 48a, 49a respectively. The turntable 41 is held against vertical displacement by means of the flattened heads 52 provided on the bolts 44. A cover 53 is secured to the turntable 41 by means of screws 54, and is provided with a plurality of spaced apertures 56 to receive legs 51 provided on an adjustable back rest 58.

An air inlet funnel 6l is detachably connected to an annular flange 62 which is mounted on the front face of the housing and enclosing the air inlet opening 2|. The funnel 6l is .preferably formed in two Tparts comprising a rcylindrical member 63 and an elbow member 64, said members being connected for relative rotational movement by means of annular coactin'g beads 66.

In the use of this apparatus for Iinishinga plaster cast denture 20, or the like, the cast is mounted upon the cover 53 with its back edge in engagement with the back rest 58. The turntable 41 is then turned to bring the peripheral wall of the plaster cast into grinding engagement 'withitne side ofthe wheeiz-z, anditfwiu be 'noted that the arcuate travel bf "the .turntable 41 :is controlled 'by 'meansof the x'ed -pivots 44, '44a and f44b coacting Withjthe several'cam surfaces 48, 48a, '49, and 49a. The limit of arcuate travel of the turntable is "controlled by the position of the stop-shoulders fl and 51a. The cover 53 is 'adapted 'to Yaccommodate casts of various lengths by adjusting the position ofthe backrest 58 with respect 'to the 'Sev'er'al `apertures 56.

The front and back faces of ltheplaster cast 22'8 maybe nishedby'holdingf'same against the side of the `Wheel 2'2, andi-t will 'be observed 'that the opening -23 iis 'shaped tto 'confll'n to 'the Youtline ofthe cast.

The cutter I9 -is-eniployed for finishing thelirregular interior 'shapeof theplaster cast 20,1a'nd said cutter lmaybe formed of metal with-suitable cuttingedge's or 'rna'ybeinltheform ef a grinding wheel.

It is `sometimesnecessary-to employ well known grinding'and cutting tools fthe type Aheld m'a'nuauy vand operated `through a :motcrand flexible shaft Yfor finishing artificial dentures. 'The-air inlet `:funnel-lil is then employed forluselto receive l5 particles of material being 'removed from the denture, and it will be noted thattheelbo'w secltio'n 64 may be rotated vto the most convenient position rfOr the `@Literatur `viluing this "finishing operationt 'During the operation-of -this grinding'and trimminglappaatuspthe bl''wer24 acts tofdraw 'streams ofairthrough the openings l2| vand2'3 to direct entrained particles of material into the blowerchamber 3| and thence through the outlet opening 26 into the dirt storage bag 21. It will be noted that the bag 21 may readily be removed Ifrom the housing 6 for the purpose of removal of dirt therefrom by merely raising the cover 38 and disconnecting the clamping band 34.

An electric lamp 66 is mounted on the front panel of the housing above the openings 2l and 23 and provided with a rsuitable reflector 61 for directing light downwardly upon the plaster cast during the nishing operations.

While this invention has been shown in but `one'form, tit is obvious to those skilled in the art that it is not so limited but is susceptible of various changes and modifications without departing from the spirit and scope of .the claimed invention.

1 claim as my invention:

l. In an apparatus of the character described, alhou'sing, Vsaidfhousing having a-pair-of air finlet openings l'formed Ain one wall thereof, 1a shaft journ'aled 'wi-thin said housing, -a cutting wheel mounted on the end Aof fsa'i. shaft 'to project ,through one of said lair -inlet openings, -a discshaped grinding Wheel mounted on 'said shaft adjacent the inner surface of the Vwall 'formed with the air inlet openings whereby material to be Vformed vmay be inserted through thelother of said openings forfengagement against said grinding wheel, a shelf provided onsaid housing, a turntable mounted on said shelf, fcam surfaces formed -on-saidturntable, and -a plurality of .fixed pivot pins secured-to said shelf vfor engagement With said Jcam surfaces to "direct said turntable along 'a predetermined line Aof movement.

y2. In an apparatus of the-character -described, a housing, said housing 'having an air inlet 'opening-formed in one wall thereo`f,afsl'iaft `journ'a'led within said housing, a disc-'shaped `grinding wheel mounted on said shaft adj acent-the inner Vsurface of the 'wall formed with the air -inlet opening whereby Ymaterial Vto be formed 1may cbe inserted through V4said 'opening lfor engagement against said grinding wheel, "a shelf *provided on said housing, a turntable mounted 'on-:said shelf, 'cam surfacesformed on'saidturntablaanda plurality of fixed fpivot pins Isecured'to said shelf f'orengagement with said cam surfaces to direct'said turntable along a predetermined line of movement.

iL. fNIEMAN. 

